1. Game can be played on network and over the internet?
2. Make dll of that application and integrate with msn messanger or skype?
3. Add chat capability to game
4. Select Image or browse image to upload to play game and that image will be used instead of "X" or "o" in the game
5. Users can play with each other or can also play with PC. For PC levels of playing game can also be set "Easy", "Medium", "Hard".
6. Record the scores in the XML file to view highest scorers

The main query is that I never made a game before and never worked with XML file. Also i never worked in network programming in C# as i did in java long time before.

Can somebody suggest me what knowledge i need to know before start programming following.

As I know many application of tictactoe are there on internet but i want all coding myself with help of your people as i got very good response in this forum.